In a bowl mix together ground beef, sausage, dried parsley, dried onion, sage, and salt. Form into meatballs about 1 1/2 inches in diameter (about 30 meatballs). Place mushrooms, onions, water, and gluten-free soy sauce into the Instant Pot. Add the meatballs. Cook on high pressure for 35 minutes. Once time is up quick release the pressure.
Using an immersion blender, purée the cooked mushrooms, onions, and water into a nice creamy gravy. Add meatballs back into the gravy and serve over rice.